[Potentiation of cytotoxic effects of 5-fluorouracil by inosiplex on cancer cells].

Inosiplex, a 3:1 molarcomplex of N, N-dimethylamino-2-propanol-p-acetamidobenzoate and inosine, which has been reported to exhibit antiviral activity in vitro and in vivo, enhanced cytotoxic effects of 5-fluorouracil (5-FU). Effects of inosiplex on the potentiation of cytotoxicity of 5-FU were investigated in vitro and in vivo. In vitro studies demonstrated that cytotoxic effects of 5-FU on cloning efficiency of HeLa cells were prominently enhanced by inosiplex, while inosiplex alone showed no cytotoxicity at the concentrations examined. Further, the survival time of mice intraperitoneally inoculated with Ehrlich ascites tumor cells was investigated. The mean survival time of mice treated with the combination of 5-FU and inosiplex significantly prolonged as compared with that of control animals or mice treated with inosiplex alone or 5-FU alone. Since inosiplex has been clinically studied as an antiviral agent and proved to be harmless to humans, the present results indicate that a combined administration of 5-FU and inosiplex may be effective in the treatment of human cancers.